Question

我的问题：我的删除节点方法适用于从用户创建的列表中删除任何指定的节点，但第一个元素除外。如何让这种方法能够删除列表的前面？

public void deleteNode(node spot, node front) {
    node current = spot, previous = front;

    while(previous.next != current) {
        previous = previous.next;
    }
    previous.next = current.next;
}

这是完整的程序代码。

import java.io.*;

public class LinkedList {
public int num;
public node front;

//set front to null
public void init() {
    front = null;
}

//make a new node
public node makeNode(int num) {
    node newNode = new node();
    newNode.data = num;
    newNode.next = null;
    return newNode;
}

//find the end of a list
public node findTail(node front) {
    node current = front;

    while(current.next != null) {
        current = current.next;
    }
    return current;
}

//find a specified node
public node findSpot(node front, int num) {
    node current = front;
    boolean searching = true, found = false;

    while((searching)&&(!found)) {
        if(current == null) {
            searching = false;
        }
        else if(current.data == num) {
            found = true;
        }
        else {
            current = current.next;
        }
    }
    return current;
}

//delete a specified node
public void deleteNode(node spot, node front) {
    node current = spot, previous = front;

    while(previous.next != current) {
        previous = previous.next;
    }
    previous.next = current.next;
}

//add nodes to the end of a list
public void add2Back(node front, int num) {
    node tail;

    if (front == null) {
        front = makeNode(num);
    }
    else {
        tail = findTail(front);
        tail.next = makeNode(num);
    }
}

//add nodes after a specified node
public void addAfter(int num, node spot) {
    node newNode;
    newNode = makeNode(num);
    newNode.next = spot.next;
    spot.next = newNode;
}

//print out a list
public void showList(node front) {
    node current = front;

    while(current != null){
        System.out.println(current.data);
        current = current.next;
    }
}

public static void main(String [] args) throws IOException{
    //make a new list and node
    LinkedList newList = new LinkedList();
    node newNode = new node();
    //add data to the nodes in the list
    for(int j = 1; j < 10; j++){
        newList.add2Back(newNode, j);
    }
    //print out the list of nodes
    System.out.println("Auto-generated node list");
    newList.showList(newNode);

    //ask the user how many nodes to make, make those nodes, and show them
    System.out.println("Please enter how many nodes you would like made.");
    BufferedReader inputReader = new BufferedReader(new InputStreamReader(System.in)) ;
    String inputData = inputReader.readLine();
    int listLength = Integer.parseInt(inputData);
    LinkedList userList = new LinkedList();
    node userNode = new node();
    for(int j = 1; j < listLength; j++) {
        userList.add2Back(userNode, j);
    }
    userList.showList(userNode);

    //ask the user to add a new node to the list after a specified node
    System.out.println("Please enter a number for a node and then choose a spot from the list to add after.");
    BufferedReader inputReader2 = new BufferedReader(new InputStreamReader(System.in)) ;
    String inputData2 = inputReader2.readLine();
    BufferedReader inputReader3 = new BufferedReader(new InputStreamReader(System.in)) ;
    String inputData3 = inputReader3.readLine();
    int newNodeValue = Integer.parseInt(inputData2);
    int nodeInList = Integer.parseInt(inputData3);
    userList.addAfter(newNodeValue, userList.findSpot(userNode, nodeInList));
    userList.showList(userNode);

    //ask the user to delete a specified node
    System.out.println("Please enter a node to delete.");
    BufferedReader inputReader4 = new BufferedReader(new InputStreamReader(System.in)) ;
    String inputData4 = inputReader4.readLine();
    int nodeToDelete = Integer.parseInt(inputData4);
    userList.deleteNode(userList.findSpot(userNode, nodeToDelete), userNode);
    userList.showList(userNode);
}
}

Answer 1

问题是您的deleteNode没有修改列表的front成员变量，因为front中的deleteNode变量是方法参数，而不是实例变量front。

以下是您需要做的事情：

将front公开为LinkedList的公共成员是违反封装的。将front设为私有变量。
从所有接受它的方法中删除参数front;请改为使用私人会员front。
在deleteNode中添加一项检查，以查看要删除的地点是否为front。如果是，则执行一项特殊操作，为front分配一个新值，然后退出;否则，执行您已经拥有的while循环。

Answer 2

public void deleteNode(node spot, node front) {
    node current = spot, previous = front;
    if(front == spot) {
        front = null;
        return;
    }
    while(previous.next != current) {
        previous = previous.next;
    }
    previous.next = current.next;
    current = null;
}

您开始检查front.next。所以front每次都被忽略了。

Answer 3

Delete a node from linklist in PHP by just passing that value to
linklist delete method....

<?php

class ListNode
{

    public $data;

    public $next;

    function __construct($data)
    {
        $this->data = $data;
        $this->next = NULL;
    }

    function readNode()
    {
        return $this->data;
    }
}


class LinkList
{

    private $firstNode;

    private $lastNode;

    private $count;


    function __construct()
    {
        $this->firstNode = NULL;
        $this->lastNode = NULL;
        $this->count = 0;
    }




    //deleting a node from linklist $key is the value you want to delete
    public function deleteNode($key)
    {
        $current = $this->firstNode;
        $previous = $this->firstNode;

        while($current->data != $key)
        {
            if($current->next == NULL)
                return NULL;
            else
            {
                $previous = $current;
                $current = $current->next;
            }
        }

        if($current == $this->firstNode)
         {
              if($this->count == 1)
               {
                  $this->lastNode = $this->firstNode;
               }
               $this->firstNode = $this->firstNode->next;
        }
        else
        {
            if($this->lastNode == $current)
            {
                 $this->lastNode = $previous;
             }
            $previous->next = $current->next;
        }
        $this->count--;  
    }



}




    $obj = new LinkList();

    $obj->deleteNode($value);


}

?>

Answer 4

linklist删除方法....

<?php

class ListNode
{

    public $data;

    public $next;

    function __construct($data)
    {
        $this->data = $data;
        $this->next = NULL;
    }

    function readNode()
    {
        return $this->data;
    }
}


class LinkList
{

    private $firstNode;

    private $lastNode;

    private $count;


    function __construct()
}

从列表中删除节点

4 个答案: